The purpose of this proposal is to continue support of a two-year postdoctoral fellowship that will attract individuals with a strong commitment to transdisciplinary research from a wide variety of backgrounds from medical, biological, social, behavioral, and policy sciences to help build the next generation of scientific leaders in tobacco control. The need for tobacco control experts continues to grow with Congress' recent legislation granting the US Food and Drug Administration authority to regulate tobacco products, passage of health care reform, with its emphasis on disease prevention and the implementation of the WHO Framework Convention on Tobacco Control, the world's first public health treaty. Our program is emblematic of the innovative cancer prevention training needed to give young scientists the tools to conduct research in collaborative transdisciplinary settings and to be future leaders in catalyzing the integration of multiple disciplines and translation of science to policy and clinical practice. We have one specific aim: Train postdoctoral fellows who will be qualified and well-positioned to become leaders in the future development and implementation of research-based tobacco control policy and interventions. This aim is met through a combination of transdisciplinary coursework related to health policy, biostatistics, tobacco control policy and prevention and treatment of tobacco-related addiction and disease combined with research directed by a primary and secondary mentor from different disciplines. The coursework forms the foundation for an intensive research program directed by two mentors from different disciplines. Fellows also learn how to prepare, submit, and review grant proposals and submit proposals to external funding agencies for their third year of fellowship funding. Research mentors include 30 faculty members with active research programs from all four schools at UCSF (Medicine, Nursing, Pharmacy and Dentistry). Mentors' research interests include tobacco control policy development and evaluation, the tobacco industry as a vector for cancer and other diseases, tobacco industry marketing strategies, tobacco addiction and its prevention and treatment, health effects of smoking and secondhand smoke exposure, smokeless tobacco, and individual- and community-based smoking cessation. The great variety in backgrounds and interests of fellows housed in the UCSF Center for Tobacco Control Research and Education provides a strong transdisciplinary environment that creates continuous opportunities to learn from and appreciate the work done by colleagues working in other disciplines. Each fellow's program is individually developed by the fellow, his or her mentors, and the Fellowship Advisory Committee that monitors his or her progress. The Committee also selects fellows from a very competitive pool: In 2010 there were 40 applications for 4 slots. During the first 4 years of this R25T our fellows have produced 77 papers in 48 different peer reviewed journals. The training program actively supports the career development and placement of our fellows; 8 assistant professors, 3 with nongovernmental health organizations, 1 with a health research consulting firm and 1 full time mother of a small child with an unpaid academic affiliation. We use the R25T mechanism rather than a discipline-based T32 because our program emphasizes transdisciplinary training and communication through unique individually tailored programs of didactics and mentored research.